The present invention relates to an automatic switch for controlling electric loads; and more particularly to an intelligent automatic switch which includes the functions of counting and storing in memory the net number of persons entering and leaving an enclosure or room to automatically control actuation/deactuation of lights or other home appliances to the room or enclosure.
Switches with automatic control capabilities are widely used for security or personal convenience in both residential and industrial applications. Most of the conventional automatic switches in the prior art simply turn on electric lights whenever a person moves through a detection pattern of a motion detector. Typically, conventional automatic switches employ a pyroelectric infra-red detector known as PIR detector as the motion detector for sensing the infrared energy emitted by a human body. However, the infrared motion detector is limited by its limited detection pattern and often cannot cover the entire area or volume of a room. Although the problem may be solved by positionally locating more sensors in the enclosure or room, this possible solution will increase the system costs. Furthermore, the detection pattern of the detector may still be blocked by furniture or other objects in the room and the switch may erroneously actuate appliances.